P05F0Reductant Pump Supply Voltage Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- The electric supply pump in the diesel exhaust fluid (DEF, AdBlue) tank module builds the dosing pressure for the SCR catalyst. Its supply voltage is monitored separately from the pump control circuit (P208A ff); CARB requires SCR components and their outputs to be checked for circuit faults and function. P05F0 means the supply voltage is too high, or voltage is present although the supply is switched off (short to battery). GM's 6.6 L diesel monitors this as P1044 (two trips); Ford flags pump voltage above 16 V or controller voltage above 19 V. No manufacturer document available to us uses this exact code; GM and Ford monitor the same function under their own codes. Without supply the pump cannot build pressure, dosing stops and NOx rises; pressure or SCR efficiency codes may follow.
- What you may notice
- Check engine light on
- DEF/AdBlue warning, possibly countdown to no-restart
- Follow-up codes for low DEF pressure or SCR efficiency
- Likely causes
- LikelyPump supply shorted to battery positive in the harness
- PossibleOvervoltage from the charging system or a jump start
- PossibleMoisture or corrosion causing leakage current in the connector
- RareRelay or driver does not switch off
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.